Field of the Invention
The invention relates generally to medical imaging, More specifically, the invention relates to patient-specific analysis of positron emission tomography data.
Background of the Invention
The early diagnosis, appropriate staging, and the subsequent assessment of treatment outcomes of various malignancies can be enhanced by modern imaging techniques. In 1956, Warburg suggested that many malignant cells utilize anaerobic consumption of glucosepyruvate, as the primary energy source. Two decades later, Bustamonte et al proposed using radiolabeled glucose for cancer detection since glucose metabolism in malignant cells may exceed two hundred times the glycolytic rates of normal non-neoplastic cells. Consequently, the application of these findings has expanded significantly by using radiolabeled 18F deoxyglucose (FDG) positron emission tomography (PET) for physiologic imaging of malignancies, often combined with computed tomographic (CT) imaging for anatomic detail.
The key to correct interpretation of the 18 FDG PET-CT image data sets is to be able consistently to differentiate between normal uptake, abnormal-nonmalignant uptake, and abnormal-malignant uptake of the radiopharmaceutical. One way this can be accomplished is by visual comparison of uptake in the target lesion with that in the mediastinal blood pool or liver parenchyma. Such a qualitative approach is subjective and may be associated with poor reproducibility. Readily applicable, less subjective evaluations may be possible with 18 FDG PET using count statistics that reflect uptake of 18 FDG. The Standard Uptake Value (SUV) for potentially differentiating malignant and non-malignant disease is one such application. The SUV is an actual measurement of the amount of 18 FDG within a region of interest corrected for the administered dosage of FDG, time of injection, and the patient's body weight.